feat: add auth support for Github, Google, Linkedin

[cbaker6]

New Pull Request Checklist

• I am not disclosing a vulnerability.
• I am creating this PR in reference to an issue.

Issue Description

Currently, developers have to manually create an authData dictionary with the correct credentials to login or link user accounts. This can be more error prone and makes it harder to unlink users.

Related issue: #55

Approach

Add auth support for the Github, Google, and Linkedin, similar to the other authentication methods. Completion block test cases aren't needed anymore as those methods get tested automatically when the async/await and Combine methods are tested.

TODOs before merging

• Add tests
• Add entry to changelog
• Add changes to documentation (guides, repository pages, in-code descriptions)

[parse-github-assistant]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[codecov]

Codecov Report

Merging #307 (6a1104a) into main (3bf2471) will increase coverage by 0.68%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #307      +/-   ##
==========================================
+ Coverage   83.87%   84.56%   +0.68%     
==========================================
  Files         105      114       +9     
  Lines       11256    11661     +405     
==========================================
+ Hits         9441     9861     +420     
+ Misses       1815     1800      -15     

Impacted Files	Coverage Δ
...cation/3rd Party/ParseApple/ParseApple+async.swift	100.00% <ø> (ø)
...tion/3rd Party/ParseApple/ParseApple+combine.swift	100.00% <ø> (ø)
...thentication/3rd Party/ParseApple/ParseApple.swift	82.50% <ø> (ø)
.../3rd Party/ParseFacebook/ParseFacebook+async.swift	100.00% <ø> (ø)
...rd Party/ParseFacebook/ParseFacebook+combine.swift	100.00% <ø> (ø)
...cation/3rd Party/ParseFacebook/ParseFacebook.swift	100.00% <ø> (ø)
...on/3rd Party/ParseTwitter/ParseTwitter+async.swift	100.00% <ø> (ø)
.../3rd Party/ParseTwitter/ParseTwitter+combine.swift	100.00% <ø> (ø)
...tication/3rd Party/ParseTwitter/ParseTwitter.swift	100.00% <ø> (ø)
...Authentication/Protocols/ParseAuthentication.swift	72.44% <ø> (ø)
... and 11 more

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